U.S. patent number 6,652,909 [Application Number 10/237,653] was granted by the patent office on 2003-11-25 for method of manufacturing composite roofing and building cover material with integrally formed nail tabs.
Invention is credited to Robert F. Lassiter.
United States Patent |
6,652,909 |
Lassiter |
November 25, 2003 |
Method of manufacturing composite roofing and building cover
material with integrally formed nail tabs
Abstract
A composite roofing material includes a final condition
underlayment material having bonded thereto appropriate rows of
nail tabs preferably made of thermoplastic-based material, such as
low density polyethylene material, and of a contrasting color to
the underlayment material. A process is used to make the nail tabs
by conveying the saturated underlayment material in a continuous
process past appropriate sets of nozzles that are coordinated with
the speed of conveyance to deposit the tabs while in a liquid state
and to form tabs of appropriate size and appropriately patterned
across the underlayment surface. Each nozzle can include multiple
orifices to control the width and thickness of the formed tabs. A
similar process is disclosed for making other building cover
materials having rows of nail tabs coinciding with standard stud
spacing.
Inventors: |
Lassiter; Robert F. (Levelland,
TX) |
Family
ID: |
27067571 |
Appl.
No.: |
10/237,653 |
Filed: |
September 4, 2002 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
561816 |
Nov 22, 1995 |
6451409 |
|
|
|
544300 |
Oct 17, 1995 |
|
|
|
|
Current U.S.
Class: |
427/210; 427/256;
427/422; 427/424 |
Current CPC
Class: |
E04D
12/002 (20130101); Y10T 428/24405 (20150115); Y10T
428/24802 (20150115); Y10T 428/24818 (20150115); Y10T
428/24843 (20150115); Y10T 428/2481 (20150115); Y10T
428/24826 (20150115); Y10T 428/24901 (20150115); Y10T
428/24893 (20150115) |
Current International
Class: |
E04D
12/00 (20060101); B05D 001/00 (); B05D
001/26 () |
Field of
Search: |
;427/209,210,258,261,286,421,422,424,442,443,186 ;428/141,147
;52/408,518,782.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Chen; Bret
Assistant Examiner: Fletcher, III; William Phillip
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application is continuation of Divisional application Ser. No.
08/561,816 filed Nov. 22, 1995, now U.S. Pat. No. 6,451,409, which
is a continuation-in-part of application Ser. No. 08/544,300, filed
Oct. 17, 1995, now abandoned entitled "Roofing Material with
Integrally Formed Nail Tabs" by the same inventor.
Claims
What is claimed is:
1. A method of making a composite roofing material, which comprises
treating an extended length of dry felt material with asphalt to
make saturated felt material, depositing a plurality of nail tabs
made of a thermoplastic or thermosetting material in a liquid state
onto the surface of the saturated felt material at a plurality of
locations, said material solidifying and bonding to the surface of
said saturated felt material to form the nail tabs.
2. A method of making a composite roofing material in accordance
with claim 1, wherein said nail tabs are thermoplastic-based
material.
3. A method of making a composite roofing material in accordance
with claim 1, wherein said thermoplastic or thermosetting material
is dispensed from nozzles, the design of said nozzles determining
the widths of said tabs in line with each of said respective
nozzles.
4. A method of making a composite roofing material in accordance
with claim 3, wherein said thermoplastic or thermosetting material
is dispensed from nozzles, the opening in each nozzle being in the
form of a plurality of closely spaced orifices.
5. A method of making a composite roofing material in accordance
with claim 1, wherein said thermoplastic or thermosetting material
is dispensed from nozzles, the openings of said nozzles being in
the form of an elongated slit.
6. A method of making a composite roofing material in accordance
with claim 3, further comprising an "on" time and "off" time for
each of said nozzles to form a preselected pattern of said nail
tabs, the "on" time for each nozzle determining the length of said
tabs therefrom and the "off" time for each nozzle determining the
spacing between tabs for a row of tabs in line therewith.
7. A method of making a composite roofing material in accordance
with claim 4, and comprising moving said saturated felt material at
a controlled rate of speed, utilizing on/off controlled nozzles for
depositing said nail tabs in a liquid state at a plurality of
locations, the deposited nail tabs from each of said nozzles
forming a separate row of tabs in line with the movement of the
saturated felt material, and timing the on/off conditions of said
nozzles so as to stagger the positions of the tabs transverse to
the movement of the saturated felt material.
8. A method of making a composite roofing material in accordance
with claim 7, wherein said moving of the saturated felt material
and timing of the on/off conditions of said nozzles determine the
dimensions and spacing of said tabs.
9. A method of making a composite roofing material in accordance
with claim 8, wherein the length of each tab is determined by
##EQU3##
wherein t equals the time that the nozzle from which the tab is
made is turned on, 1 equals the length of the tab, and S equals the
speed of movement of the saturated felt material.
10. A method of making a roofing material in accordance with claim
8, wherein the spacing of the leading edges of two adjacent tabs
formed from the same nozzle is determined by ##EQU4##
wherein T equals the duration between the time that said nozzle is
turned on for the first of said two adjacent tabs and is turned on
for the second of said two adjacent tabs, L equals the distance
between the leading edges of said two adjacent tabs, and S equals
the speed of movement of the saturated felt material.
11. A method of making a composite building cover material, which
comprises horizontally moving a sheet or board of the building
cover material at a controlled rate of speed, and utilizing a
plurality of on/off controlled nozzles spaced apart at intervals
for depositing from each of the nozzles a plurality of nail tabs
made of a thermoplastic or thermosetting material in a liquid state
onto the surface of the building cover material at a plurality of
locations, said material solidifying and bonding to the surface of
the building cover material to form the nail tabs.
12. A method of making a composite building cover material in
accordance with claim 11, further comprising timing the on/off
conditions of the nozzles so as to stagger the positions of the
tabs transverse to the movement of the building cover material.
Description
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
Field of the Invention
This invention pertains to roofing materials or other building
materials normally employed as cover materials prior to the
installation of roofing shingles or external building finish siding
and more specifically to such cover materials incorporating therein
a plurality of integrally formed nail tabs.
A shingle roof installation generally comprises at least two
distinctive layers. The first layer is an underlayment, usually a
saturated asphalt material that attaches directly to the plywood
sheets or board material that supports the shingles. The second
layer is made up of the shingles themselves. Normally, the
underlayment assists in making the roof resistant to water
intrusion. The starting material for the underlayment is a base
material usually referred to as "dry felt". Examples of types of
dry felt starting material are rag, paper and fiberglass, which is
not exhaustive of possible starting base materials. The starting
base material that has actually been subject to experimentation is
a fibrous paper made from treating recyclable cardboard; however,
this invention is not limited thereto. The term "dry felt" used
herein is used generically for all suitable starting base material.
Dry felt material when saturated with an asphalt material produces
an underlayment roofing material known in the trade as "tar paper"
or "saturated felt", which is produced in various grades depending
on thickness and weight.
Regardless of the type of underlayment roofing material that has
been employed, common practice in the installation industry has
been to unroll a length of the underlayment material and affix each
length to the support sheets or boards at a plurality of locations
so that it stays in place prior to the installation of the covering
shingles. The affixing or fastening devices for this material are
generally staples and nails. Staples and regular nails are readily
applied by power devices; however, both are notoriously susceptible
to either pulling out of the sheets or boards when there is an
uplift on the underlayment or, when the staples or nails stay in
place, tearing of the roofing material at the fastening locations.
Even when shingling is to follow immediately, the underlayment can
still be exposed alone to windy and other adverse conditions, such
as when the installers walk or crawl on the underlayment.
Moreover, it is desirable that the underlayment be securely
attached independently of the shingles not only in the
pre-shingling stage of installation, but also in the final
installation. This is because shingles do get blown or ripped off
under adverse weather conditions and a securely independently
installed underlayment will provide some interim protection from
the weather elements prior to roof repair. When the underlayment is
not securely fastened, then the underlayment may be blown away or
ripped concurrently with shingle damage.
To securely install the underlayment and avoid the tearing
described above, it has long been a common practice to either use
roofing nails with large heads or to use an auxiliary large washer
or tab that lies underneath the nail head. Such large washer or tab
successfully resists being torn through as with a smaller nail head
of regular size. The use of such washer or tab has not been totally
satisfactory, however, since such use is time consuming, somewhat
expensive, and can be somewhat dangerous when the installation is
on a fairly steeply pitched roof and/or the conditions are
inclement. This is because it requires two hands to either slip the
washer over the nail or to hold a tab down while driving the nail
through. If the installer is having to reach while only supporting
himself or herself on a toeboard, it may be uncomfortable and/or
unstable to be unable to use either hand for additional support
when necessary. Moreover, nails with large, unconventional heads
are not recommended both because they are expensive and because
they cannot be used in ordinary power equipment. Ordinarily, power
equipment for driving nails can be loaded only with standard nail
cartridges.
U.S. Pat. No. 5,365,709, commonly owned herewith, describes an
improved underlayment roofing material that includes a plurality of
suitable nail tabs attached to a felt base. The concept therein
described was to produce a roll of underlayment that had the tabs
in place so that the installer would not have to separately handle
a washer or a separated tab and nail. With the tabs in place, the
installer would merely target the tabs one by one with a
conventional power driven nail gun. Such installation would be many
times faster than installations previously described and would be
less cumbersome to the installer since the nailing process would
not require both hands when a nail gun is used. However, the
underlayment therein described has not been used commercially. To
make a dry felt material with glued-on tabs, as described in the
'709 patent, into saturated felt material requires the adhesive and
the tab material to not materially degrade during the asphalt
saturation process. The high temperature of this process and the
rollers used tend to either melt the adhesive glue, melt the tab
material itself, scrape off the tabs, or a combination of all
three, any of which renders the resulting saturated felt material
unreliable, if not unsuited, for commercial use.
It has been discovered, as hereinafter described, that tabs can be
permanently and reliably affixed or bonded to saturated felt
material avoiding many of the problems attendant to affixing tabs
to the dry felt base material as described in the '709 patent.
Moreover, it has been discovered that the process of producing
suitable tabs onto saturated felt material can be automated using
liquid thermoplastic tab material that quickly solidifies and
adheres or bonds to the surface of the saturated felt material.
Also, importantly, it has been discovered that the production of
tabs onto the saturated felt material can be done immediately
following the step of dipping or spraying the dry felt material
with a suitable hot asphalt mix to make saturated felt material.
Thus, the conversion of dry felt to saturated felt can be combined
in an automated process with the subsequent production of the
tabs.
In addition to saturated felt material used in a roofing
application, suitable tabs can also be similarly installed using
liquid thermoplastic tab material to other base sheeting materials,
such as siding materials used for wrapping the side of a framed
house or other structure prior to securing the finish siding.
Therefore, it is a feature of the present invention to provide an
improved sheeting material having nail tabs produced directly onto
at least one of its surfaces.
It is another feature of the present invention to provide an
improved underlayment roofing material incorporating nail tabs
therein that are tough and compliant that are produced directly on
saturated felt material.
It is yet another feature of the present invention to provide such
an underlayment roofing material incorporating nail tabs therein
that are of a material that is reliable when used in the extremes
of ambient temperature conditions encountered in typical
installations.
It is still another feature of the present invention to provide an
improved underlayment roofing material utilizing an automated
process for applying a liquid thermoplastic material at appropriate
tab positions using nozzles that are readily programmably
controlled.
It is yet another feature of the present invention to provide an
improved underlayment material, wherein the overall process is
continuous and automated to include the saturation of dry felt
material to make saturated felt material followed by the production
of suitable nail tabs from pressurized liquid thermoplastic-based
or other material that subsequently hardens and securely bonds to
the surface of the saturated felt material.
SUMMARY OF THE INVENTION
A composite roofing material is made starting with a roll of dry
felt material. In the preferred method of producing the
underlayment roofing material in accordance with this invention,
the dry felt material is introduced to the beginning of a
continuous and automated process having a system of driven rollers
for transporting the roofing material through the process. First,
the dry felt material undergoes treatment in conventional fashion
to produce asphalt saturated felt material from the dry felt
material. Then, a suitable liquid thermoplastic-based or other
material is deposited on the rapidly moving saturated felt using
appropriately positioned nozzles or nozzle sets. The on/off
operation of the nozzles or nozzle sets and the movement of the
saturated felt material are respectively controlled and coordinated
by one or more suitable programmable microprocessors. The
thermoplastic-based material may include an appropriate adhesive to
ensure that it bonds to the surface of the saturated felt material
as it rapidly cools and hardens to form the desired nail pads or
tabs. The thermoplastic-based material may be reinforced with
fibers, flakes or other similar particles, and such material may
also include a color contrasting dye to that of the underlying
saturated felt material, which is normally black. Even without an
added dye, however, the tabs do contrast in color and are readily
visible.
By the time the saturated felt material with tabs reaches a "free
looper" stage, the tabs are sufficiently cooled and hardened to
operational conditions. That is, they are tough, but flexible. The
free looper is followed by a final stage, where the underlayment
material with tabs is wound to make up standard sized rolls. The
free looper allows this action to occur without impacting on the
prior continuous movement of the conveyed saturated felt during the
foregoing tab producing stage of the operation.
As mentioned, the final resulting composite roofing material just
described is manufactured using a machine that includes one or more
depositing nozzles at each row location. The liquid
thermoplastic-based or equivalent material is normally supplied to
the depositing nozzles under pressure. The nozzles are turned on
and then off to deposit the material in the correct quantity and at
the correct spacing, which preferably staggers the tabs across the
width of the base felt material. The line speed of conveyance
determines, through the operation of a microprocessor, the
durations of both the "on" time and the "off" time.
Each "nozzle" used for making the deposits is preferably either a
plurality of closely spaced orifices in a common manifold housing
or an elongated slit opening so as to cover a wide enough area for
making tabs of the preferred width dimension without forming a tab
that is too thick. When a plurality of orifices are employed, the
liquid material flowing from the individual orifices blends
together, cools and hardens to form the individual tabs.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features, advantages
and objects of the invention, as well as others which will become
apparent, are attained and can be understood in detail, more
particular description of the invention briefly summarized above
may be had by reference to the embodiment thereof which is
illustrated in the appended drawings, which drawings form a part of
this specification. It is to be noted, however, that the drawings
illustrate only a preferred embodiment of the invention and is
therefore not to be considered limiting of its scope as the
invention may admit to other equally effective embodiments.
In the drawings:
FIG. 1 is a schematic side view of an automated process of
manufacturing a composite roofing material of the invention in
accordance with a preferred procedure.
FIG. 2 is a schematic top view of the nail tab production area of
the automated process shown in FIG. 1.
FIG. 3 is a schematic representation of a nozzle with a manifold
housing having a plurality of orifices used in the process of
manufacturing the composite roofing material as shown in FIG.
2.
FIG. 4 is a schematic representation of a nozzle having an
elongated slit used in the process of manufacturing the composite
roofing material as shown in FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The making of the composite roofing material preferably employs a
machine manufactured by Nordson Corp. of Westlake, Ohio that uses
one or more nozzle sets for dispensing multiple beads of viscous
liquid, as set forth in U.S. Pat. No. 5,335,825, which is
incorporated herein for all purposes. This machine has been
utilized in the past, for example, in laying down small beads of
glue onto stock cardboard, which when subsequently cut and folded
produces boxes. Other suitable equipment can be used, if
desired.
The process illustrated in FIG. 1 is generally a roller driven
system that moves from left to right in the drawing. The end of a
roll 10 of appropriate dry felt material to be saturated is
conveyed using a drive roller 12 to a treatment area 14 for asphalt
saturating the dry felt in conventional fashion. This saturating
treatment stage is illustrated as a series of turns of the unrolled
felt material since that fairly represents how the material is fed
through the hot asphalt bath or pit to saturate the dry felt
material. The temperature of the asphalt that is applied is
typically in excess of 400.degree. F. As the saturated felt
material exits the saturating treatment stage, it may be cooled by
use of a water cooled chill roll 16. Other means of cooling the
saturated felt may be used, if desired For example, conveying the
material through a long distance in a cool ambient environment
would produce the same cooling result.
It has been discovered, however, the subsequent production of the
nail tabs can be produced without detriment onto the surface of the
saturated felt material even though this felt material is at an
elevated temperature near to the temperature condition that it
leaves treatment area 14. Thus, there is no need for use of a rapid
cool-down scheme for the saturated felt material. The only
cool-down that is required is for the felt material to be
sufficiently cooled at the end of the procedure to permit being
wound into conventionally sized rolls, as hereafter described.
As the felt leaves treatment area 14, it is saturated felt material
17. Material 17 is driven in direction 24 through the nail tab
production area 18 by a plurality of driven rollers 22a, . . . 22x.
Although only two rollers are shown in the illustration for
convenience, an actual system will have multiple rollers in area
18. They are driven by a motor and drive system (not shown) well
known in the art at a speed that is selected by an operator. The
line speed of felt material 17 in area 18 is closely monitored by
microprocessor 29 connected to roller 22a.
The thermoplastic-based material to be dispensed onto the surface
of the moving saturated felt material is dispensed from nozzles or
nozzle sets 26 as provided from a pressurized supply tank and pump
system 28. The typical thermoplastic-based material is also heated
to a liquid state in system 28 or as it is introduced to system 28.
A preferred example of a suitable thermoplastic-based material is a
low density polyethylene compound EA839, a proprietary blend
produced by Eastman Chemical Corp. Such a compound includes one or
more suitable adhesives that enhance the bonding of the material to
the surface of the saturated felt material. The compound may also
include a suitable contrasting dye color, such as red, to make the
tabs stand out against the normally black background color of the
saturated felt. Without an added dye, the material is amber in
color, which naturally contrasts somewhat in color to black. Other
suitable thermoplastic-based materials can be selected such as
ethylene vinylacetate, or if desired, a thermosetting-based
material such as a two component polyurethane.
Color can also be provided independently of a dye put into the
thermoplastic-based material. For example, it can be fed to the
nozzle from an independent source to be combined with the
thermoplastic material just before nozzle dispensing and as the
application takes place.
Regardless of the nail tab material used, it must be either
fast-cooling or fast-setting so that it bonds and solidifies to the
surface of the saturated felt before it leaves line area 18. The
tabs, as they are bonded to the material, are tough, but remain
flexible or pliable and not brittle. Normal operating conditions
for roof installations are from below ambient freezing conditions,
i.e., below 32.degree. F., to above 120.degree. F. The
characteristics for tabs must be as above-described over this full
temperature range.
Returning to FIG. 1, the liquid material to be dispensed from
nozzles 26 is dispensed at a temperature of about 350-450.degree.
F., preferably at about 425.degree. F., and at a pressure of
between 1300-1500 psi. Each orifice opening is about 0.026 inches
in diameter. The saturated felt material underneath the nozzles may
have only dropped to about 315.degree. F. from the temperature of
about 400.degree. F. of treatment area 14 at the time the material
is deposited thereon from nozzles 26. The tabs that are formed are
identified by numerals 29a, 29b, . . . 29x. The on/off timing of
nozzle 26 and the rate of movement of the saturated felt material,
i.e., line speed, is programmably matched by microprocessor 30, as
described more fully below. Generally, however, microprocessor 30
controls the "on" time and "off" time of applicator nozzles or
nozzle sets 26 so that the dimensions and spacing of the tabs are
correct. The operation of microprocessor 30 is coordinated in
operation with microprocessor 29 monitoring the line speed.
As the saturated felt with tabs attached leaves line area 18, it
passes by grooved wheel 32. The grooves in grooved wheel 32 permit
the tabs to pass through without being subject to possible scraping
action. From wheel 32, the felt enters into "free looper" 34 and
from there to make up roller area 36. Roller area 36 is where the
final rolls are produced. Typically, #30 weight saturated felt
material is cut and rolled in 70-foot lengths and #15 weight
material is cut and rolled in 140-foot lengths. The line speed
preferably moves at between 300-800 ft. per minute. Thus, every 6
to 12 seconds for a felt material movement of 700 ft. per minute,
the material is cut, a roll is finished and a new roll is
started.
Now referring to FIG. 2, a top view of saturated felt material 17
is shown in line area 18. Three nozzles 26a, 26b, and 26c are shown
for forming three linear rows of tabs parallel with the elongate
dimension of material 17. A sheet of saturated felt material is
typically 3-feet wide. In actual practice, there can be more than
three rows. The tab size is exaggerated for illustration purposes,
but, typically, one row of tabs is produced near the front edge of
material 17, another row of tabs is produced near the back edge,
and a third row of tabs is produced mid-way between these edge
rows. The front row of tabs, including tabs 29a and 29b, is
produced from the liquid material dispensed from first nozzle
26a.
One preferred embodiment of a suitable nozzle is a manifold housing
being opened in the form of a plurality of individual, but closely
spaced orifices. Five or six such orifices have been successfully
employed. These orifices are shown in line transverse to the
direction of movement of felt material 17; however, they can be in
some other pattern, if desired. The number of these openings
generally determines the width of a produced tab. Each of nozzles
26a, 26b, and 26c is connected to pressurized tank and pump 28 and
controlled in on/off operation by microprocessor 30, which, in
turn, is closely coordinated in operation with line-speed
monitoring microprocessor 29. It will be seen that it is preferred
that the production of tabs produces a staggered arrangement of the
tabs across or transverse to the moving direction of felt 17.
Preferably, the tabs are square, but they may be rectangular or
other shape. In FIG. 2, the length of a tab is defined as "1". If
the time of application or "on" time for a nozzle is defined as "t"
and the line speed of the material is defined as "S", then the
formula ##EQU1##
applies where t, l and S are expressed in consistent units.
To calculate, for convenience, how long it would take to form a
1-inch long tab for a line speed of 600 ft. per minute, the answer
would be about 0.0083 seconds. The preferred operation coordinates
the operation of the nozzles to the line speed via microprocessor
30 so that as the line speed may vary, the tab lengths will remain
substantially uniform. Separately controlled line speed and nozzle
operation can be performed, however, if desired. Alternately, a
single microprocessor combining the operations of microprocessors
29 and 30 can be employed.
The spacing of the tabs is determined by the "off" time of the
nozzles. For convenience of calculation, the distance from the
leading edge of tab 29a to the leading edge of tab 29b is defined
as "L". The time between tabs is defined as "T". Therefore, the
following equation applies for calculating the distance L:
##EQU2##
The preferred width and length dimensions of tabs are between
0.75-1.5 inches. The thickness of a tab is typically about 0.04
inches. The spacing distance of the tabs is normally 1 to 3
feet.
FIG. 3 shows a close up view of tab 29a being formed in the
dispensing of material from a nozzle 26a having five in-line
orifices 40, 42, 44, 46 and 48. As the material flows out of the
orifices in a liquid state, the width of the tab becomes slightly
larger than the distance between the outermost orifices before it
begins to harden. Also, note that the liquid from each of the
orifices runs together with adjacent deposits so that the formed
tab has a uniform thickness dimension when it hardens. Fewer or a
greater number of orifices can be employed, if desired.
FIG. 4 illustrates an alternate nozzle structure wherein nozzle 50
has a single elongate slit 52 that is positioned transverse to the
movement of felt material 17.
Although the above description has been with regard to providing
tar paper or saturated felt material with integrally formed nail
tabs, other covering sheets or boards of building material can be
similarly treated. For example, cover sheets of siding materials
employed before installing the final or finished siding can employ
suitable rows of nail tabs spaced compatibly with the spacing of
studs. Stud spacing is standard in a locale as determined by local
building codes, but studs are typically spaced apart either 16
inches or 24 inches. Therefore, nail rows of the appropriate
predetermined standard interval spacing can be provided so that
when the siding is put in place, the nail rows will be centered on
the studs. An installer can then secure the siding in place quickly
with a nail gun targeting the tabs, which will also target the
studs.
Although the siding may be in sheet form, it can also be in board
form. Typical styrofoam board sheathing is 4 feet by 8 feet by 1
inch. Again, nail tabs as hereinabove described can be provided
appropriately spaced to center on the studs. When the boards are
thus positioned, then targeting the nail tabs by an installer using
a nail gun will also target the studs. Boards can be made with
integrally formed nail tabs by appropriately positioning the
nozzles to formed rows at appropriate intervals and then feeding
the boards through area 18 of FIG. 1 in a manner similar to feeding
rolled sheet material in the process previously described.
Therefore, while a particular embodiment of the invention has been
shown, it will be understood that the invention is not limited
thereto. Many modifications may be made and will become apparent to
those skilled in the art For example, if nail tabs are to be made
on the reverse side of the roofing material as well as on the top
side, the material with nail tabs on a first side is merely run
through a second set of nozzles after first being passed over a
reversing roll.
* * * * *